SkillLite FS: 中心化文件操作
模块：
- read_write: read_file, write_file, append_file, atomic_write
- dir: read_dir, list_directory, file_exists, create_dir_all, copy, rename, remove_file, modified_time
- grep: grep_directory
- search_replace: apply_search_replace, apply_replace_fuzzy, insert_lines_at
- backup: backup_file, prune_oldest_files
- util: is_likely_binary, matches_glob